1. Force Diagrams 8 th Grade Science

2. Forces We know that a force can be a push or a pull acting on an object There is a good chance that 2 forces can be acting on an object at any one time Examples: –Lifting something –Dragging something –Floating Globe

3. Balanced Forces If two equal forces are applied to an object in opposite directions, the object does not move / or moves as a constant speed. This is called balanced forces.

4. Unbalanced forces If two unequal forces are applied to an object in opposite directions, the object does move. This is called unbalanced forces. And someone will win!!

5. Unbalanced Forces If the forces acting on an object are not balanced then the object with either: –Speed up –Slow down –Change direction –Chance its shape Fill in the Gaps sheet

6. We can use force diagrams to show this: 4N7N The block has 2 opposing forces being applied to it: 7N to the right and 4N to the left. They are Unbalanced Forces. To Calculate the Resultant Force (Fr), subtract one from the other: 7N – 4N = 3N to the right 3N

7. Problem: A man of mass 75kg has a weight of 750N. This 750N will act downward on the table and the table will exert a 750N force upwards on the man. The forces are balanced. What would happen if the upward force were less than 750N? Force down 750N Force up 750N

8. Your go: Draw a force diagram with the following characteristicsng: 1.200 N east 2.300 N west 3.Describe the motion of the object, including the direction and the overall force acting on that object

9. More on Balanced and Unbalanced Forces: Collect and complete the following worksheets: –More on Balanced and Unbalanced forces –Floating and Sinking (Read p101) –Parachutes (Read p101) Extension Work: –Text book: Starting Science for Scotland Book 2, Read p22, Ans Q1-4 Base Jumping

10. Moments Questions…

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